Does anybody know if there is a benefit to having two volume controls as on a Series I/II vs having a blend knob? I am considering having a blend knob on a future instrument to cut down on the number of total knobs.

I don't know if "benefit" is the right word, it sounds a lot different is all I know. As I said back in the dark ages of the birth of this club somewhere in a thread: "it's the difference between 'and' and 'or'". I set the bridge PU in a certain position I like. Mostly volume wide open and the filter and CVQ on a certain position. This done I ADD a portion of neck PU with that volume knob which sounds deeper but again the filter and CVQ set in a position i find myself comfortable in, in that given situation. With a blend knob it's about "or": you take a part of the bridge PU and you can only have more of the neck PU iff you take lesser bridge. In a way: a blend is easier to use. A two volume knob setting is more versatile but a liitlemore complicated for finding the right setting for you a-in a certain situation. Mostly there are volume issues. What is logical because it is about "adding" two PU's. I guess it's why the master-volume is not a bad idea to add.

Certain players, like BKBass, prefer individual volumes AND a master volume as opposed to a master/blend scheme. There is a method to this madness: it is more flexible. The blend can be frustrating if you need multiple tones and value quick settings repeatability (i.e., as in a live "cover" band situation).

Thanks for your input. My main issue is that the guitar I would like to have made includes a Roland GK pickup and a small standard body. Valentino already told me that some things will have to go. One of them is the 1/4 in cable output. I would like to keep this feature so I am considering getting rid of the pickup selector and the individual volumes. I hope this saves enough space to keep the 1/4 in output. I just wanted to make sure that this would not be a fatal blow to the Alembic sound.

There was a long discussion on this a while back, which (in my opinion) was inconclusive.

The "and/or" concept that Paul describes is a nice way of describing how you, as a person, interact with the controls. However, I (and a few others) am convinced that mathematically, you can get exactly the same range of possible pickup combinations with either two volumes, or a pan. They are just two different ways of adjusting the relative contributions of two pickups.

I don't believe anyone offered a satisfying explanation of *why* they would end up sounding different. (There were a few distractions, such as a couple of cases where the pan control wasn't implemented quite right and gave uneven results, but that's a different issue.)

I remain unconvinced that they fundamentally sound different, and personally prefer a pan. In fact, if I did have separate volumes, then I would also want to have a master volume.

To me it's a matter of how you need/want to use the controls, and there are good reasons for either approach, depending on your style. I really don't believe there is any reason to believe you would be sacrificing "the Alembic sound", so if the pan is what fits for you, then go for it. -Bob

I only know the pan control on my two Alembics, and the whole idea of having to juggle two pots sounds awkward to me. In fact nearly as awkard as having only a pickup switch and a single volume, like originally on my Spoiler - it's so much more versatile with a pan! As far as I can recall, the extreme and middle positions of the pan sound much the same as the corresponding positions of the pickup selector. But the in-betweens - ah! it's a totally different animal.

But we all seem to be speaking here in terms of a single-channel rig, and therefore a blended signal. I can't recall having heard of a Series or Anniversary package with a pan. Would that be just because of the extra circuitry involved to match the levels in two unblended signals, or is it an electronic no-no?

Personally, I'm not a fan of the master/pan set-up on my EMW-equipped Orion (with bass/treble cut/boost, filter an "Q" sw.). I prefer the Series I set-up with the master vol. and p/u selector switch. It makes repeatabilty of settings a little easier with the latter, as opposed to the former. Just having a filter and 3pos. "Q" for each p/u is a little simpler than ( a master set-up with) two tones and a filter w/"Q". I know, I know: I like to repeat the word "repeatabilty" ad naseum, LOL!

I have both styles of controls. I have never had any issues with the pan versus individual volume controls. I find the pan easy to use for getting repeatable results. To be quite honest I have found my simplest bass (Essence electronics with Q switch) to be the easiest to get repeatable settings. I say go with whatever you are most comfortable with.

I have a couple of schematics that show how to wire a pan pot as a pair of volume pots, stacked and reversed. These can then be wired to a selector and then a master volume (which could be stereo, now that I think about it.) I'm sure with the alembic electronics it's not that simple but I like the idea of having both a blend and a selector switch.

here is a stupid(ish) question. when you switch to a single pickup on a Series II does the volume setting revert to the master or does it stay at the individual volume setting? ie; if you have the bridge on full, the neck just leaking in a bit, and the master at half and then turn the switch to the neck position is it still just leaking through or does it come up to the half volume setting of the master?

It is still just leaking through. The only thing that changes is the bridge pickup goes out completely. The volume would drop big time. It kind of works like a mixer with the pickup volumes being channel faders and the master volume being...a master volume.

You could drop the pickup selector and keep the two volumes. In that case you lose the option to switch off either pickup completely without changing the volume, and you also lose the mute position - so if you can live with that ...

I notice that on my '99 Rogue, the overall volume increases slightly when the blend pot is in either full neck or full bridge position. Is there some sort of function which attenuates the volume of one pickup as the other pickup is blended in? It seems like there is, as the volume stays consistent throughout the rest of the range of the blend. Alternately, is it possible that there is a phase problem?

Charles; I was thinking that maybe I had heard of this problem before, but I couldn't find any posts on it. I may have been thinking of a somewhat similar issue with Signature electronics; but it wasn't quite the same thing. Interestingly, several years ago I was using a wireless with my Essence, and anytime I moved the pan control full to one end or the other, I would get an audible click. (I think it was the Pan, but my memory just isn't very reliable.) But it only happened when I was using the wireless. After I stopped using the wireless, it was no longer an issue. Anyway, this sounds like a question for Mica. If she doesn't notice this thread, you may want to post the question in the troubleshooting section.

The issue was raised here and it was with Signature electronics, but I believe the fix was applicable to Europa electronics as well. I believe it was available as a self-installable fix if you are comfortable with a soldering iron, but I never followed up to get the cost.

I did some seaching and I think the posts may have been lost in the reorganization or upgrade of the boards. I did find a message from last May where you made reference to the fix, Dave, but that's about it.

I couldn't find it either, though I am likewise convinced that a problem was discussed, as well as a simple fix, roughly a year ago. Actually, I thought the inconsistent volume issue was right around the center, rather than at the two extremes, but I don't trust my memory any more than Dave does his these days :-)

I didn't even find the post by Dave from last May, mentioned above... but came across these two that are interesting in terms of the original question:

Thank you for the links Bob. I don't know how I missed this conversation. I usually keep up with most of the posts. After reading this I am once again questioning which way I should go. I think I may still have some time to decide before the electronics go into the guitar.

Real Estate seems to be the underlying problem here.Let me offer a few things to consider; Alembic likes to have an inch spacing between knobs so between making a 3/4" space in conjunction with smaller THG knobs might sqweak another knob or two on the instr.,another possibility might also be to use an RMC piezo bridge system with the Roland electronics eliminating the need to change any of the knobs that would be standard to the Alembic way of doing things.I think the RMC pickup may be around $300.00. But it can be used with any synth module.

I don't believe the RMC unit will work in an Alembic. The RMCs are six individual bridge saddles, like on a strat. Both of my guitars with the RMC system have the strings loaded through the back, unlike an Alembic. The RMC uses the 13 pin conductor used by Roland guitar synths. It requires two controls: a volume knob, and a three way momentary toggle switch.

my wolf was volume/pan val is a big believer in 2 volumes since its been back at the factory for repair we have replaced the pan with a second volume it comes down to increasing volume or decreasing as opposed to reducing the sound out of on of the pickups i think there is more room for better sound with 2 volumes

I bumped into this discussion months after it went fallow, but had a few comments. So here they are!

There *IS* a difference between dual volumes and pan that has to do with the physical reality of how the blend pot works.

As you probably already know, pots are constructed with what's called "taper". A potentiometer is a variable resistor, but, because you're ears hear logarithmically instead of linearly, the pot is constructed so the "halfway" point isn't half the resistance, it's actually much higher resistance.

The decibel scale reflects your ear's non-linear response as well. This is why you see those confusing descriptions like "2x the power only gives you 3dB more volume" and "twice as loud takes 10x the power". Both comments are true, by the way, but it good part is that you can usually piss off your neighbors with less than 10 watts RMS, so you should have too much problem getting yourself arrested with a 200 watt amp.

Anyway, because of this response curve, pots that are intended for volume use have what's called an "audio taper". The resistance is adjusted so "halfway" will be perceived by your ears as half as loud. This allows you to have finer control of the output level across the rotation of the knob. If you used a linear taper potentiometer, then turning down "halfway" wouldn't seem to have much effect and all the control of the volume would be at the last, lowest part of the rotational range.

With two volumes, you use two audio taper pots (which gives you optimal control of the volume of each pickup) and sum the outputs. A master volume is another audio taper pot following the pickup volume on a mono instrument or a ganged set of audio taper pots on a stereo instrument.

This is why the blend knob can be problematic. You want the pot to decrease one pickups volume as the other increases. If the blend pot could be linear taper, then this isn't that hard to do (although there are caveats below). But the blend pot is the only way you are going to control the pickup output levels, so you really want that pot to be audio taper.

But that doesn't work either! A single audio taper pot set up for blend works great for one of the pickups (because it's just a regular pickup volume!), but the taper is totally backwards for the other pickup, which won't work at all. So, usually when you see blend pots, it's a ganged potentiometer (two pots turned in concert by the same shaft), one of which is regular audio taper and the other one which is reverse audio taper (works just like audio taper but wired for reverse rotation). Now each pickup sees the proper audio taper and you can sum the outputs to get your sound.

But this doesn't work exactly right either. When you're fully on bridge or neck pickup it's fine (all one pickup, none of the other). But when you put the blend pot in the middle, both pickups are now turned halfway down, as opposed to both pickups being set to full output on a dual volume setup. This is part of the reason why blend basses often seem to have lower output in the middle position, although most of that is coming from phase cancellation since the two pickups aren't "hearing" the string in the same place.

On a passive Jazz Bass, a blend knob like this is a real problem. When you turn down the volume pot on a passive bass, you're increasing the series resistance, and because the tone control and cable present a parallel capacitance, you end up rolling off the highs as you turn the volume down. So, a blend knob on a Jazz bass is bad news because it's the same as turning both pickups down halfway, and will dull the tone.

On a bass with active electronics, the tone is independent of the volume, and there's effectively no high end rolloff when you turn the volume down. But you have to have the blend knob AFTER the onboard preamps for it to work properly. That means you can do this on a Series bass where each pickup has it's own preamp, but on all the other Alembics, there's only one preamp, and the blend knob would have to be before that. That means that you will be suffering from the blend side effects. Incidentally, EMG pickups have the preamp built into each pickup, so that's another case where the blend knob can work properly.

People are clever, so you can actually buy a special blend pot at places like Stew-Mac that tries to fix this problem. Here, they build a ganged pot that has special tapers in each element. One side has an audio taper for half it's rotation, then stays at full volume for the other half of the rotation. The other side is full volume for half the rotation, then reverse audio taper for the other half. When you use a pot like this, in the center position both pickups are at full volume, so there's no treble loss, and one pickup or the other tapers off to either side. This is pretty good, but if you think about this, you're now blending a fraction of one pickup against the full output of the other pickup. You should be able to dial in any relative ratio, but it's still not exactly the same. You can dial in 100:60 for sure, but you can't really get 80:48. And, if you remember, because this mixing is happening before the preamp, there really will be a tonal difference between 60% and 48%.

At this point, the effects are pretty subtle and the utility for some with the blend is worth it. But if you really want maximum control of your tone and blend, dual volumes will technically give more control than a blend pot.

Minor correction to David's quite illustrative post. In addition to the Series instruments, Signature and Europa electronics have two preamps as I believe also do the Distillate, Elan and Spoiler. I believe the electronics packages with a single preamp are the Persuader, Essence, and Epic/Orion. I can't recall the configurations of the guitar packages.

The best single summary I've seen of single vs twin preamps for Alembics is here.

Thanks for the education, Dr. Fung - we were sort of short on facts here. So to cut to the chase, for those who might get lost in the noise, is it your opinion that for an Alembic with two preamps, the difference between two volumes versus a pan is pretty much a matter of convenience or choice, and not a significant issue of sound quality?

Thanks for the correction! I'm lucky to own three Series basses, but don't have that much direct knowledge about the other models. I can't believe I still don't have a Distillate, as I really loved the sound of the ones I played in the distant past. I don't think I've ever seen one outside of the Alembic booth at a NAMM show, also in the distant past. They must be rare indeed when you have a better chance of seeing a used Series bass in a store.

When each pickup has a preamp before they are summed, then there's little effect on tone as you reduce the level (whether by pickup volume or blend control). So, from a tonal standpoint, I think that separate volumes vs pan should be identical in the two-preamp cases.

If you have a passive two-pickup bass like a Jazz, you can be surprised at how much effect turning the volume has on tone. Of course, as you turn down, the volume level drops (!) so it's easy to write the differences off, but if you try turning a pickup volume down and increase the amp gain so it's a simliar level, you'll probably be suprised at how different it sounds.